1. Field of the Invention
The present invention relates to light emitting diode substrate modules and a method of manufacturing the same, and backlight units and a method of manufacturing the same.
2. Description of the Related Art
In general, image display devices for displaying images are included in various kinds of electronic apparatuses, such as mobile communication terminals, digital cameras, laptop computers, monitors, and TVs. Various kinds of image display devices can be used. However, flat panel displays having a flat-panel shape are generally used in terms of characteristics of the electronic devices. Among the flat panel displays, liquid crystal displays (LCDs) are widely used.
The liquid crystal display is one of the flat panel displays, and displays an image by using liquid crystal. As compared to other flat panel displays, the liquid crystal display is thin and lightweight, and has a low driving voltage and less power consumption. For these reasons, the liquid crystal display is used widely across all industries.
The liquid crystal display includes a liquid crystal display panel displaying an image by using light and a backlight unit providing light to the liquid crystal display panel.
The backlight unit includes a light emitting diode substrate module that uses small light emitting diodes as light sources in consideration of product characteristics. The light emitting diodes constitute point light sources that have a small emitting area.
The light emitting diode substrate module is divided into a direct type and an edge type according to the arrangement of the light emitting diodes that form point light sources. The direct type light emitting diode substrate module includes a plurality of light emitting diodes that are arranged below a liquid display panel. The edge type light emitting diode substrate module includes a plurality of light emitting diodes that are arranged at the edge of one side of a light guide plate. The direct type light emitting substrate module is generally used for a backlight unit of a large TV. The edge type light emitting substrate module is generally used for a backlight unit of a mobile display or a computer monitor.
FIG. 1 is a configuration view illustrating a light emitting diode substrate module according to the related art. FIG. 2A is a cross-sectional view illustrating a backlight unit according to the related art. FIG. 2B is a plan view illustrating the backlight unit according to the related art.
As shown in FIG. 1, a direct type light emitting diode substrate module 1 includes a substrate 2, and a plurality of light emitting diode packages 5. The substrate 2 has excellent heat conductivity and a driving circuit formed on an upper surface thereof by patterning. Each of the plurality of light emitting diode packages 5 includes a package body 4 mounted with a light emitting chip 3, and is mounted onto the upper surface of the substrate 2 to receive an electric driving signal.
The backlight unit 10 includes a plurality of metal chassis 11 that are secured by a plurality of fastening members and are mechanically fixed to the bottom.
A gap pad 12 may be additionally embedded and disposed between a lower surface of the substrate module 1 and the bottom of the metal chassis 11 so as to improve heat radiation characteristics.
However, when the light emitting diode substrate module 1 is manufactured, in order to form the mechanical driving circuit by patterning, a copper film is applied over the entire surface of the substrate 2 without considering an area of the copper film that is actually required, which causes a waste of the copper film.
Further, a white or whitish protection mask in which TiO2 is contained in a polymer in order to prevent an area of the driving circuit formed on the surface of the substrate 2 by patterning. The protection mask is discolored due to deterioration of the polymer during a mounting process to reduce reflection characteristics. For this reason, an additional reflective plate needs to be provided at a front surface of the substrate.
When the backlight unit 10 is manufactured, the substrate module 1 may be mounted to the metal chassis 11 by using various kinds of assembling methods, each of which includes an assembling process of securing the substrate module 1 to the metal chassis 11. Therefore, it takes a time to perform the assembling process, and at the same time, an additional structure, such as the gap pad 12, is required.
Further, fastening holes 13 and 14 need to be provided in the substrate 2 and the metal chassis 11. The assembling process is complicated due to the additional process of forming the holes.
Furthermore, the plurality of substrate modules 1 mounted to one metal chassis 11 need connectors 15 to electrically connect one substrate to another substrate adjacent to the substrate, which increases the number of components and time to perform the assembling process.